Selector-switch.



M. K. MCGRATH.y

SELECTOR SWITCH.

APPLICATION FILED IuNE 23. |916.

1,245,481 Patented Nov. 6, 1917.

Maur/'ce K. M3. @raf/z.

UNITED STATES PATENT oEEIcE.

MAURICE K. MCGRATHV, OF NEW YORK, N. Y., ASSIGNOR TO WESTERN ELECTRICCOM- PANY INCORPORATED, OF NEW YORK, N. Y., A. CORPORATION 0F NEW YORK.

SELECTOR-SWITCH.

Specication of Letters Patent.

Patented Nov. 6, 1917.

i Application led J une 23, 1916. Serial No. 105,412'.

To all whom z't may concern.'

Be it known that I, MAURICE K. Mo- GRATH, a citizen of the UnitedStates, residing at New York, in the county of New York and State of NewYork, have invented certain new and useful Improvements inSelector-Switches, of which the following is a full, clear, concise, andexact description.

This invention relates to automatic or semi-automatic telephone systems,and has as one object the securing of a preliminary location of a linewhen in a certain condition, and subsequent relocation and associationof a calling line therewith.

Heretofore, when it has been desired to select a group of terminal setsand find one of that group which is in a given condition, as not busy,it has been customary to primarily step a brush set from group to groupuntil the desired group has been reached. The brush set then remainsstationary until a change in circuit conditions causes it to beginhunting over the group to find a terminal set in the desired condition.This seriously lilmits the present automatic systems using directimpulse control because the brush set has to wait at the selected groupa suiliciently long time to determine that the last impulse has arrived,that is, it must wait for the change-over before it will begin to huntin that group. It is essential that the terminal set be found and adistant machine placed in a receptive condition before the sender canoriginate another train of pulses; but it has been found in practicethat, in the short time between series of impulses, the mechanism isoften unable to complete its action, and that the next train of pulseswill result in obtaining a wrong connection.

One of the objects of this invention is the utilization of this timeinterval, hitherto wasted,1in which the brush set stood still, t effectsearching for the desired line, and thus the searching operation will beCompleted before a succeeding series of impulses can be sent. Thisresults in greater rapidity in securing the desired connection, thusincreasing the eiiiciency of the system and making it ossible for thesame number of trunks to handle an increased number of calls, withresultant saving 'of equipment.

A still further object is to effect preliminary hunting for a line athigh s eed and, after the line is located, to researc for said.

line at a slower speed and connect therewith.

Referring to the drawing, Figure 1 shows 1n part the mechanicalconstruction of the stop and brush-operating mechanism, and also showsdiagrannnatically the circuits and apparatus which constitute oneembodiment of the invention.

In the preferred form of the invention, the general operation is asfollows. A stop 1s moved under impulse control to the deslred group.Movement of the stop releases a brush carriage which follows the stop bygravity. When the brush carriage is with- 1n one group or less of theposition of the stop, a circuit is prepared through a test relay, sothatwhen a line in a desired condition is passed by the brush carriage,this prepared circuit is completed. The completion of this circuitswitches in a return mechanism to cause the return of the brush set to`permanent 'connection with'the line previously located.

Referring first to the brush carriage which is normally in the positionshown in Fig. 1, 1 is a brush support and carries a multiple brush set 2which is moved on actuation of an elevator rod 3 over the sets ofterminals of a contact bank 4, thel sets of contacts being divided intogroups for a purpose to be later described. This elevator rod 3 has aseries of openings therethrough corresponding in number to the number ofrows in the terminal bank, and a locking pawl 6 to normally engage thelowermost of said openings. This lockingI pawl 6 is moved by an armature7 under the control of a high-speed magnet 8. A gear wheel 9 has teethalso engaging the openings 5 and is rotatably mounted on a shaft 10whichl carries a ratchet wheel 11. The wheels 9 and 11 are connected bya spring coupling 12 which normally tends to hold the wheels in theposition shown in Fig. 1. A stop- .arm 13, secured to the ratchet wheel11 and movable therewith, normally engages a stop 14 on the wheel 9under the influence of the spring coupling 12. An insulating member 15is secured on the wheel 9, and on this is mounted a commutator ring 16of conducting material. This commutator ring has a conducting segment 17adjacent the stop 14, of a length equal to the distance moved by the arm13 on one step of the ratchet wheel- 11, and arranged to be wiped overby the arm 13. The purpose of this conducting segment is to prepare acircuit from grounded battery 18, brush 19, conducting shaft 10,conducting ratchet wheel 11 and stop-arm 13, segment 17, commutator ring16 and brush 20, test relay 46 and other apparatus to be laterdescribed, when the wheel 9 and registering position.

The ratchet wheel 11 is normally held -against back movement by a catchpawl 21 controlled by an armature 22 of an escapement switch resetmagnet 23. On attraction of the armature 22, the pawl 21 is drawn downand forced out of engagement with the wheel 11 by a pin 43 fixedlycarried on the structure supporting the shaft 10. The wheel 11 isstepped forward on actuation of a primary or group stepping magnet 24which pulls up its armature 25, forcing forward a pawl 26 to stop thewheel 11 one step on each actuation of said magnet 24. The updrive ofthe elevator rod 3 is accomplished by a secondary or clutch magnet 26which, when energized, pulls up its armature 27 to force the elevatorrod 3 against a constantly rotating updrive roller 28.

The operation of the device is as follows: The subscriber at station 100removes his receiver from the hook and when his line 101, l02visextended through a line inder or other suitable device to wires 103,104, the line relay 29 is actuated to send current through and pull upthe slow-break relay 31. When the first series of impulses is sent bydial 109, the circuit to the line relay is intermittently broken. Eachtime the armature 30 drops back, it completes a circuit from ground,back contact of armature 30, front contact of armature 32, and wire 36to the group stepping magnet which steps the wheel 11 one step for eachimpulse. At the first break of the line relay` circuit, a circuit iscompleted through the slow release relay 33 vwhich pulls up its armatureto completeia circuit to actuate the high speed magnet 8 to withdraw thelocking pawl 6. This circuit is as follows: grounded battery 38, magnet8, front contact and inner armature 34 of relay 33, conductor 39, rearcontact and left-hand armature 40 of relay 46, conductor41, back contactand outer lefthand armature of relay 72,to ground. Relay 33 isunaii'ected by the short breaks incident to the sending of the grouimpulses. On the movement of the stop an the withdrawal of the lockingpawl, the brush carriage drops by gravity aided by the springcoupling12. The actuation of the group stepping magnet will set the stop for acertain group and when the brush carriage gets within one step, thestop-arm 13 will engage the conducting strip 17 of the commutator andprepare a circuit from the battery 18,

brush 19, wheel 11, stop-arm 13, segment 17, commutator 16, brush 20,wire 45, relay 46, back contact and armature 48, side-switch wiper 49 totest brush 50 which, in passing over the group, completes the circuitfrom ground through a grounded contact 51 of the first idle trunk in thegroup. This actuates test relay 46, which locks itself up and energizesclutch magnet 26 to step said brush carriage back. The locking circuitextends from ground, battery 18, brush 19, shaft 10, stop-arm 13,segment 17, commutator 16, brush 20, conductor 45,-relay 46, conductor54, front contact and left-hand armature 40 of relay 46, conductor 41,back contact and outer left-hand armature 42 of relay 72 to ground. Thetest relay 46 also prepares a circuit for the relay 61 which controlsthe circuit of the escape switch 63 and the updrive magnet 26. In'thebank 4, idle trunks or lines have ground placed on their test contacts.The test contact 51 belongs to an idle line and hasv ground thereon asshown. As the brushes passed rapidly over grounded contact 51, the relay61 would not ordinarily be actuated. If, for any reason, the brushpassed the contact 51 sufficiently slowly to energize relay 61, no harmwould be done, as the relay 61 would at once pull up, thereby preventingcurrent being furnished the clutch magnet 26 to step it back bycompleting a circuit for the escape magnet 63 which moves the sideswitch into its second position, and the brush would be left inengagement with the desired line. Assuming the brush has passed athigh-speed, only the relay 46 would act, locking up its circuit and alsocompleting a circuit for the clutch magnet 26. The high-speed magnet 8would have been released and the carriage locked in place as soon -asthe test relay 46 acted, the circuit of magnet 8 being opened at theback contact of armature 40. The updrive will continue until thegrounded brush in the group is reached, when a circuit from ground, testcontact 51, brush 50, arm 49, front contact of armature 48, wire 60,through relay 61, to grounded battery 62, would energize relay 61 toopen the circuit of the clutch magnet and close a circuit for the escapemagnet. The circuit for the escapeswitch magnet extends from groundedbattery 65, escape magnet 63, front contact and outer armature 66 ofrelay 61, conductor 67, back contact andvouter armature 64 of `relay 33(denergized by the long energization of the line relay 29 at the end ofthe first series of impulses), conductors 68, 41, and back contact andouter lefthand armature 42 of the release relay 72, to ground. Theescape magnet, on energization, moves the switch arms to second ortalking position.

Inertia of the carrier may carry it a few contacts below the contactinitially located and, if any of these contacts are in the desiredcondition, the carrier will return until it reaches the rst of thesecontacts in that condition, whereupon relay 61 will act and associatethe brush with that contact, as previously described.

Should the carriage havefound an idle trunk in a group before thecompletion of the sending of the group impulses, the stoparm would bemoved a full step and the circuit between the stop-arm 13 and segment 17to test relay 46 would be broken before the magnet 33 could havereleased the circuit to the magnet 8 controlled by armature 34. Thehigh-speed magnet 8 would be held up and, on further movement of thestop, the carriage 9 would follow to relocate a terminal set in theproper group. In the second position of the side switch, the clutchmagnet 26, line relay 29, group ,stepping magnet 24, and relay 33 havetheir circuits opened.

In the second position, the talking circuit is extended through wires105, 106 and their brushes to wires 107, 108, leading directly orthrough intermediate selectors and connectors to the called party.Thereuponrelay 69 is energized to cut off ground from the test contact51 by a circuit extending from battery 53, left-hand winding of relay69, conductor 108, calling circuit, wire 107 and right-hand winding ofrelay 69 to ground. The relay 72 has its armatures 7 74 and 42 made slowto pull up to insu e the energization of rela 69 and consequent cuttingoi of ground rom contact 51, before relay 72 could possibly act. Relay69, on pulling up, prevents actuationof the relay 72 opening the circuitat the armature 52 and back contacty of rela 69.

magnet 72 through an off-normal contact 7 5.

This circuit extends from ground, armature 30 and back contact of relay29, armature 32 and its back contact, conductor 44, sideswitch arm 80,oli-normal contact 75, and relay 72 to grounded battery. Magnet 72locksitself up, and completes a circuit for the clutch magnet 26, fromgrounded battery 59, magnet 26, conductors 58, 77, 76, front contact andouter left-hand armature 42 of relay 72 to ground. This moves thevcarriage to normal, in which position the off-normal contact will beopened and the restoring magnet denergized. On energization of releaserelay 72, a circuit is comp eted for the release magnet 23 from ground,outer armature 42 and front contact of relay 72, conductors 76, 78,magnet 23 to grounded battery 79. The magnet 23 pulls up, withdrawingthe pawl 21 from ratchet wheel 11, leaving it free to return to normal.On reaching normal, relay 72 is denergized, opening the circuit tomagnet 23, which, on its back stroke, resets the switch arms to Vfirstposition.

Should the` parts be in talking position and the receiver replaced, thetrunk relay 69- is denergized and puts ground on test terminal 51, brush50, side-switch armA 49 second position, 'wire 70, back contact ofarmature 71, restoring magnet 7 2, to ounded battery. Restoring magnet72 will then pull up and restore the device to normal.

What is claimed is:

1. In an electric switching system, a plurality of contacts, linesindividual to said contacts and connected thereto, a movable contact, aline connected therewith, means for establishing an initial connectionbetween said movable contact and one of said plurality of contacts, andmeans operated by said initial connection for moving said movablecontact to'effect a inal connection between said movable Contact and thecontact initially connected therewith.

2. In an electric switching system, a plurality of contacts, linesindividual to said contacts and connected thereto, a movable contact, aline connected therewith, means for establishing an initial connectionbetween said movable contact and one of said plurality of contacts,means for establishing a final connection between said movable contactand a contact initially connected therewith, and means operated by theinitial connection of said contacts for controlling the operation of thesaid last-mentioned means.

3. In an electric switchin system, a plurality of contacts, lines in'vidual to said contacts and connected thereto, a movable contact, aline connected therewith, means to move said movable contact toinitially locate a contact in said plurality of contacts, and meanscontrolled by the initial location thereof to move the movable contactinto association with the contact initially located.

4. In an electric switchi system, a plurality of contacts, lines inividual to said contacts and connected thereto, movable means forestablishing connection to any desired Contact, a line connected to saidmovable means, means to move said movable means at high speed until adesiredl contact is encountered, and means controlled by said l v meansat a high speed until a desired contact is passed, and means controlledin passing a desired contact to return saidl movable means at a slowerspeed to engage a desired contact.

6. In an electric switching system, a plurality of contacts, linesindividual to said contacts and connected thereto, movable means forestablishing connection to any contact in a desired condition, a lineconnected to said movable means, means to move said movable means untila contact in a desired condition Yis passed, and means controlled inpassing a contact in a desired condition to return said movable meansand associate it with the first contact in a desired conditionencountered on said return movement.

. 7. In an electric switching system, a plurality of contacts, linesindividual to said contacts and connected thereto, movable means forestablishing connection to any desired contact, a line connected to saidmovable means, means to move said movable means at a high speed until adesired contact is passed, means controlled in passing a desired contactto return said movable means at a slower speed to engage a desiredcontact, and means to lock said movable means when a desired contact hasbeen engaged.

8. In an electric switching system, a plurality of contacts, movablemeans for establishing connection to any one of said contacts when in adesired condition, means to move said movable means at high speed untila contact in a desired condition is passed, means controlled in passingsaid contact to move said movable means at a slower speed to engage thecontact in the desired condition, means to change the condition of saidcontact, and means to restore said movable means to normal on a secondchange of the condition of said contact.

' 9. In an electric switching system, a plurality of contacts, a movablecontact carriage,- a contact thereon to engage any one of said pluralityof contacts, a stop for said carriage, means including a circuit forcontrolling the movement of the carriage, and means to change thecondition of said circuit when said carriage and stop are within acertain distanceof each other.

10. In an electric switching system, a plurality of contacts, a movablecontact carriage, a contact thereon to engage any one of said pluralityof contacts, a stop for said carriage, and means to cause the movablecontact to begin searching for a contact in a desired condition whensaid carriage and stop are within a certain distance of each other.

11. In an electric switching system, a plurality of contacts, a movablecontact carriage, a contact thereon to engage any one of said pluralityof contacts, a stop for said carriage, means to search for a contact ina desired condition, and means to prevent the movable contact searchingfor a contact until said carriage and stop are within a certain distanceof each other.

12. In an electric switching system, a plurality of groups of contacts,`a movable contact to engage any desired one of said plurality ofcontacts, an impulse mechanism associated with said movable contact,means to step said movable contact from group to group under actuationof said impulse means, and means to search for a contact in the desiredcondition within a group before the completion of the impulses actuatingsaid stepping means.

13. In an electric switching system, a plurality of groups of contacts,lines individual to said contacts and connected thereto, a movablecontact, a line connected therewith, means for moving said movablecontact to any desired group, means for establishing an initialconnection between said movable contact and a contact in said group in adesired condition, and means operating immediately thereafter forassociating said movable contact with the contact initially connectedtherewith.

14. In an electric switching system, a plurality of groups of contacts,lines individual to saidvcontacts, a movable contact, a line connectedtherewith, means for moving said movable contact from group to group,and means operated by said movable contact engaging a desired contact ina desired group during said group movement for associating said movablecontact with said desired contact.

15. In an electric switching system, rality of groups of contacts, amovable contact, an impulse mechanism associated with said movablecontact, means for moving said movable contact directly from one groupto another under control of said impulse mechanism, and means operatedby said movable contact engaging a desired contact in a desired groupduring said group movement for stopping said movable contact upon saiddeslred contact.

16. In an electric switching system, a plurality of groups of contacts,a movable contact, means for locating contacts within said groups in adesired condition, means for associating said movable contact with acontact in a desired condition in any of said groups, and means toprevent location of contacts in non-desired oups.

17 In an electric switc ing system, a plu-y rality of contacts dividedinto a plurality of groups, a movable contact carrier, a contactthereon, a stop to insure stopping of the carrier on the proper group ofcontacts, means to move said stop to the desired posltion, means tocause said carrier to move toward its stop position, conducting means inengagement when the stop means and carrier are within one group of eachother, a circuit including said conducting means, the contact of thecarrier and a desired contact in the selected group, and meanscontrolled thereby to effect association of said contact on the carrierwith said desired contact.

18. In an electrically operated switch, contacts therefor, a movablecontact carrier, a Contact thereon, a stop for determining the stoppingposition of said carrier, means to move said stop, means to move saidcarrier toward its set position, a segment engaged by said stop whensaid moving means 1s within a certain distance from said stop, means forlocki said carrier, and a circuit adapted to have 1ts condition changedwhen said segment and stop are in engagement to control the means forlocking said carrier.

19. In a telephone exchange system, a calling line, impulse meansassociatedtherewith, a contact bank divided into a plurality of groupsof terminals, outgoing lines connected to said'termnals, a movable brushcarriage, a brush thereon, means to normally hold said carriage inlocked position, means to extendlthe calling line to said brush andestablish a talking circuit between the callin line and an outgoingline, means to move said brush carriage to any desired group, circuitscontrolling said holding and moving means, relay means under cntrol ofsaid impulse means to control said circuits, means to return said brushcarriage to normal position, a test circuit completed when said brushencounters a terminal in the desired group in a desired condition, relaymeans in said test circuit acting on completion of said circuit toeffect the movement of the carriage restorin means to associate saidvbrush with a de sire terminal, and relay means to effect actuation ofsaid carriage restoring means on breaking of said talkin circuit.

20. In an electric switching system, a line, a group of contacts, otherlines connected to said contacts, a movable brush carriage, a brushthereon, means for connecting said first line to said brush, means tomove said brush over said contacts, a relay, a circuit completed whensaid brush encounters a contact in a desired circuit condition, a relayin said circuit actuated thereby to extend control to said first relay,means to associate said brush with a desired contact, a circuit for saidmeans, and a circuit closed to said second relay on associationof saidbrush with the desired contact, said rst relay changing the condition ofthe circuit for the means for associating the brush with the desiredContact.

21. In an electric switching system, a pluralty of contacts, linesindividual to said contacts and connected thereto, a contact movableover said plurality of contacts to engage any desired contact, a lineconnected to said movable contact, means to move said movable contact atdifferent' speeds to engage said plurality of contacts, and meansoperated by the engagement of said movable vcontact with a contact in adesired condition to move said movable contact at a different speedthereafter.

22. In an electric switch, a `plurality of groups of contacts, linesindividual to said contacts and connected thereto, a movable contact toengage any of said plurality of contacts, a line connected to saidmovable contact, means to move said movable Contact at different speeds,and means operated by the movable contact, engaging contacts in adesired condition in a group to cause said movable contacts to move at adifferent speed thereafter.

23. In an electric switch, a plurality of groups of contacts, linesindividual to said contacts and connected thereto, a movable contact toengage any of said plurality of contacts, a line connected to saidmovable contact, means to move said movable contact at different speedsand in different directions, and means operated by the movable contactinitially engaging a contact in a desired condition in a group to causesaid movable contact to move in a different direction and at a differentspeed thereafter to again engage said contact.

24. In an electric switching system, an electrically operated switchhaving a plurality of fixed contacts and movable contacts, means forcausing said movable contacts to traverse said fixed contacts bymovements of different characters, and means operative in response tothe en agement of one of said movable contacts wit a desired fixedcontact for altering the character of movement of all of said movablecontacts.

25. In an electric switching system, a plurality of terminals, a movablecontact to engage any of said terminals, means to move said contact atdifferent uniform rates of speed to engageany desired terminal, and

means to automatically change the speed 'of said contact from one rateto another when group.

27. In an electric switching system, a plurality of terminals, a Contactto move over said terminals and engage any desired terminal, means tomove said contact at different uniform rates of speed to engage anydesired terminal, and electrical means for automatically effecting achange of speed of Said contact from one rate to another when Within acertain distance of a desired ter-v minal.

28. In an electric switching system, a plurality ,of terminals, amovable contact to engage any desired terminal, means to move saidcontact at a high speed, a circuit to op- Lawaai erate said means, meansto move said contact at a Lower speed, a circuit to operate said lastnamed means, a relay for controlling said circuits, and means toautomatically operate said relay to effect change of speed of saidY 15contact when it is Within a certain distance of a desired terminal. y

In Witness whereof, I hereunto subscribe my name this 22nd day of JuneA. D. 1916.

' MAURICE K. MGGRAIH.

